000015568 001__ 15568
000015568 005__ 20180122195846.0
000015568 037__ $$a1434-2016-118826
000015568 041__ $$aen
000015568 245__ $$aAgriculture in a Global Perspective
000015568 260__ $$c2001
000015568 269__ $$a2001
000015568 270__ $$mjonathan.harris@tufts.edu$$pHarris,   Jonathan M.
000015568 300__ $$a21
000015568 336__ $$aWorking or Discussion Paper
000015568 446__ $$aEnglish
000015568 490__ $$aWorking Paper No. 01-04
000015568 520__ $$aIn the twenty-first century, it is evident that world agricultural systems will have to supply sufficient food for a population somewhere between 7.5 and 12 billion. Projections for world agriculture in the first half of the twenty-first century very widely, largely depending on assumptions about yield growth. An investigation of the patterns of yield growth for major cereal crops offers evidence that the pattern is logistic, implying that an upper limit to yields is being approached. This pattern is consistent with ecological limits on soil fertility, water availability, and nutrient uptake. It is also evident that current agricultural production is imposing serious strains on ecosystems, with widespread soil degradation, water overdraft and pollution, and ecological impacts such as loss of biodiversity and the proliferation of resistant pest species. The issue therefore is not simply the balance of supply and demand in agriculture. It is the need to develop ecologically sustainable agricultural systems which can provide an agricultural output about twice present aggregate levels (allowing for per capita growth in consumption). This level of output would support a population of about 8 billion. In addition, a population policy which can avert any much higher growth is essential. Evidence exists to show that ecologically sustainable cropping systems can supply overall outputs comparable to intensive high-input agriculture. (The measure of overall output is distinct from the more commonly used measure of single-crop yields.) This evidence, however, is more compelling for temperate zones with good soils. Much more research is needed on sustainable agriculture for tropical and arid zones. Agricultural policies need to be reformulated to meet the new goal of sustainability. These sustainable agriculture policies must be developed in tandem with population policies to ensure that population growth remains in the lower ranges of current projections.
000015568 650__ $$aAgricultural and Food Policy
000015568 700__ $$aHarris, Jonathan M.
000015568 8564_ $$s80267$$uhttp://ageconsearch.umn.edu/record/15568/files/wp010004.pdf
000015568 887__ $$ahttp://purl.umn.edu/15568
000015568 909CO $$ooai:ageconsearch.umn.edu:15568$$pGLOBAL_SET
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  Previous issue date: 2001
000015568 982__ $$gTufts University>Global Development and Environment Institute>Working Papers
000015568 980__ $$a1434